EP0531285B1 - Clamping head for winding tubes - Google Patents

Abstract

A clamping head for winding tubes on which material in web form, such as paper webs or the like, is wound on and off has a multiple cornered clamping head shank (20) against which clamping pieces (40) rest. The clamping pieces (40) and the clamping head shank (20) can be rotated relative to each other, and this rotation causes a radial movement (expansion/contraction path) of the clamping piece (40). When the torque-dependent expansion is maintained, withdrawal from the tube is facilitated because the clamping head shank (20) is shaped as a truncated pyramid, the clamping pieces (40) and the clamping head shank (20) can be slid relative to each other in the axial direction (B), the clamping pieces (40) are provided with, or effectively connected to, an end limit stop(34) for the winding tube (10) effective in the axial direction (B) and to an end limit stop (35) fixed to the clamping head shaft (20) effective in the axial direction (B), and the clamping distance (expansion/contraction distance) of the clamping pieces (40) is composed of a rotation-related part and a sliding-related part, so that the (second) end limit stop (35) reaches its axial end position before reaching the end of the clamping distance.

Description

The invention relates to a clamping head for winding tubes of the type reproduced in the preamble of claim 1.

Such a clamping head is known from DE 1 574 438 B. It is used for winding web-like material, such as paper webs, film webs and the like. Like. Used on winding cores and also for unwinding such winding cores, with a tensioning head being clamped in a central, essentially circular recess at each end of the core, in order to transmit the torque required for winding or braked unwinding to the winding core or from the winding core. In this known clamping head, a hexagonal clamping head shaft is provided, which is surrounded by segment-shaped clamping pieces. With their radially inner surfaces (contact surfaces), the clamping pieces rest flat on the six outer surfaces of the clamping head as long as they are in their (not spread) rest position. The radial outer surfaces of the clamping pieces, which will later be brought into contact in the outer recess of the winding tube, form a circumference in the rest position which is normally less than the clear dimension of the recess at the front end of the winding tube. The clamping pieces and the clamping head shaft can be turned relative to each other. As a result, the clamping pieces can be pressed uniformly radially outward over their entire length, as seen in the axial direction of the clamping head, so that their outer surfaces in the recess of the winding tube expand non-positively. As the web winds up, the roll diameter and thus the torque to be transmitted increases. This automatically leads to an increased spreading of the clamping pieces. Now it is not readily possible, after completing a winding or unwinding process, to apply the same torque between the sleeve or the roll and the clamping head in the opposite direction, which occurred during the winding process as the maximum torque (in the other direction) . It is therefore not possible to loosen or reset the spreading device. For this reason, the clamping heads must be pulled off the winding tube in their spread working position with the application of high force.

A similar clamping head as from DE 1 574 438 B is known from DE 29 10 114 A1, the difference being that in the latter document the clamping pieces with their radially inner surfaces do not lie flat against the outer surfaces of the clamping head shaft, but rather one have circular cylindrical inner contour, which is provided with axially extending grooves and wherein elongated pressure pieces fitted into the grooves protrude radially inward with a convexly curved surface and this surface lies linearly against the six outer surfaces of the clamping head shank. With this latter arrangement, the release of the clamping head from the finished wound sleeve can be accomplished with less effort than with the clamping head known from DE 1 574 438 B.

The removal of the winding sleeves from the clamping head is easier with another clamping head type, as described, inter alia, in DE 28 15 310 C, than with the clamping heads of the type mentioned at the outset, because in this other known clamping head type one instead of a twist Axial displacement between the clamping head shaft and the clamping pieces is carried out in order to achieve the expansion or contraction of the clamping pieces. For this purpose, the sliding surfaces between the clamping head shaft and clamping head pieces are wedge-shaped. An axial stop connected to the clamping pieces, which comes to rest on the end face of the sleeve when the clamping pieces are not yet expanded, enables the transmission of a force acting in the axial direction, through which the clamping pieces slide along the clamping head shaft and thereby spread out in the recess at the end of the winding tube. The constant expansion path over the entire clamping length depends on the size of the insertion force applied in the axial direction. When the clamping head is pulled off the winding tube, the clamping head shaft first retracts relative to the clamping pieces, as a result of which the clamping pieces move radially inwards and the radial pressing force decreases. With this type of clamping head, pulling off the clamping head from the winding tube is therefore easier than with the clamping heads of the type mentioned at the beginning. This advantage is accompanied, among other things, by the disadvantage that the clamping force is exerted exclusively by the axial force exerted on the clamping heads depends. If this is too large, the winding sleeve is deformed, if it is too small, there is a risk of slipping between the winding sleeve and the clamping head with increasing torque. Both are undesirable.

Finally, from DE 37 00 472 A1 a further clamping head of the type mentioned is known, in which the clamping head shaft has not only a polygonal clamping zone with a constant cross-section seen in the axial direction, but also a frustoconical clamping zone with a circular cross-section tapering in the direction of insertion. The frustoconical clamping zone is in front of the polygonal, constant cross-section clamping zone when viewed in the direction of insertion. The two clamping zones arranged one behind the other have the purpose that one of the two clamping zones still remains effective when a force acting axially on the clamping head or a force acting on the clamping head in the circumferential direction is relieved or completely eliminated. If you want to pull the clamping head out of a fully wound sleeve, a relative twisting between the clamping head shaft and clamping pieces presents the same difficulties as is the case with the clamping head according to DE 1 574 438 B, since it is difficult or impossible to do so to apply a corresponding, oppositely effective torque to the wound sleeve. Here, the frustoconical clamping zone acts as an additional obstacle, since the surface of the truncated cone surface lies tight against the corresponding frustoconical surfaces of the clamping pieces. This known geometry of the clamping zones means that the radial clamping path of the clamping pieces, which can be generated by the frustoconical clamping zone, with the maximum clamping path that can be realized by the constant cross-section, polygonal clamping zone, must be exactly the same size; this is the only way to ensure that one of the two clamping zones can also transmit the clamping forces alone, ie without the participation of the other clamping zone.

The invention is therefore based on the object of providing a tensioning head of the type mentioned at the outset, in which the removal from the winding tube is facilitated when the torque-dependent expansion is obtained.

This object is achieved by the features set out in claim 1.

An inventive clamping head has u. a. the advantage that the radial expansion path is torque-dependent, so that damage to the winding cores, as well as slipping of the winding cores is avoided, and that the pulling off of the clamping head from the winding core is nevertheless facilitated. The advantages of the two types of clamping head mentioned at the outset are thus combined with one another without the mutual disadvantages occurring. In the clamping head according to claim 1, the advantage is also achieved that the relative position between the winding tube and the clamping head shaft in the axial direction is always exactly defined, because the expansion path is always composed of a displacement-related and a rotation-related portion, the displacement-related portion always automatically has priority because the clamping head must first be pushed in its axial direction before the twisting can begin. In contrast, the relative position between the clamping pieces (and thus also the winding tube) and the clamping head shank in the clamping heads of the second type is necessarily variable and undefined. However, this is usually undesirable.

In order to achieve that the expansion path of the clamping pieces over their entire effective lengths also with the clamping heads according to the invention is constant, a clamping head with the features of claim 3 is proposed.

If it is not so important in the specific application that the relative position seen in the axial direction between the clamping head shank and the clamping pieces is always the same, but it is very important that the expansion path is constant over the entire effective length of the clamping pieces, proposed as an alternative to the clamping head according to claim 1, the clamping head according to claim 3.

The constancy of the expansion path over the effective length of the clamping pieces is achieved in a particularly simple manner by the features set out in claim 4.

A comparatively low frictional resistance between the clamping head shaft and the clamping pieces during expansion or contraction is achieved by the features of claim 5. In addition, particularly precisely definable relative positions between the clamping head shank and the clamping pieces are thereby achieved. In addition to the rolling movement between the clamping pieces and the clamping head shaft, a certain sliding movement can also take place. The rolling movement can be realized in a particularly simple manner by the features of claim 6.

In order to automatically reset the twisting movement between the clamping head shaft and the clamping pieces after pulling off a clamping head from a winding tube, a clamping head with the features of claim 7 is proposed. Practical embodiments for this solution, which can also be used advantageously in the generic clamping heads regardless of the characterizing features of claims 1 and 3, result from claims 8 and 9.
The above-mentioned components to be used according to the invention are not subject to any special exceptional conditions in terms of their size, shape, material selection and technical conception, so that selection criteria known in the respective field of application can be used without restriction.

Fig. 1a bis 1c

einen erfindungsgemäßen Spannkopf in Ruheposition, d. h. mit völlig nach innen eingezogenen Spannstücken, wobei Fig. 1a einen Längsschnitt durch den Spannkopf (Schnitt entlang der Linie Ia-Ia gemäß Fig. 1b), Fig. 1b einen Querschnitt durch den Spannkopf gemäß Fig. 1a (Schnitt entlang der Linie Ib-Ib) sowie Fig. 1c eine Stirnseitenansicht des Spannkopfes gemäß Fig. 1a (Ansicht A, d. h. ohne Deckel) zeigt;

Fig. 2a

denselben Spannkopf nach Abschluß des durch Axialverschiebung bedingten Spannweges (Schnitt entlang der Linie IIa-IIa gemäß Fig. 2b);

Fig. 2b und 2c

die den Fig. 1b und 1c entsprechenden Darstellungen für die in Fig. 2a gezeigte Arbeitsposition des Spannkopfes;

Fig. 3a bis 3c

denselben Spannkopf in entsprechender Darstellungs-weise wie in Fig. 1a bis 1c, jedoch in einer dritten Arbeitsstellung (Wickelposition, d. h. mit fest im Wickelhülseninneren verspreizten Spannstücken);

Fig. 4a bis 4c

denselben Spannkopf in einer vierten Arbeitsposition, h. bei relativ zu den Spannstücken noch verdrehtem, aber bereits in Axialrichtung zurückgezogenem Spannkopfschaft;

Fig. 5

von demselben Spannkopf eine schematisierte Stirnseitenansicht (entsprechend Ansicht A) zur Darstellung der Relativlagen zwischen Spannkopfschaft und Spannstück mit und ohne gegenseitiger Verdrehung;

Fig. 6

eine alternative Ausführungsform des Spannkopfschaftes in der gleichen Darstellung wie in Fig. 5.

Further details, features and advantages of the subject matter of the invention result from the following description of the accompanying drawing, in which - as an example - a preferred embodiment of a clamping head according to the invention is shown. The drawing shows:

1a to 1c

a clamping head according to the invention in the rest position, ie with clamping pieces completely retracted inwards, FIG. 1a a longitudinal section through the clamping head (section along the line Ia-Ia according to FIG. 1b), FIG. 1b a cross section through the clamping head according to FIG. Section along the line Ib-Ib) and FIG. 1c shows an end view of the clamping head according to FIG. 1a (view A, ie without a cover);

Fig. 2a

same clamping head after completion of the clamping path caused by axial displacement (section along the line IIa-IIa according to FIG. 2b);

2b and 2c

the representations corresponding to FIGS. 1b and 1c for the working position of the clamping head shown in FIG. 2a;

3a to 3c

same clamping head in a corresponding representation as in FIGS. 1a to 1c, but in a third working position (winding position, ie with clamping pieces firmly spread inside the winding tube);

4a to 4c

the same clamping head in a fourth working position, h. with the clamping head shaft still twisted relative to the clamping pieces, but already retracted in the axial direction;

Fig. 5

a schematic front view of the same clamping head (corresponding to view A) to show the relative positions between the clamping head shaft and the clamping piece with and without mutual rotation;

Fig. 6

an alternative embodiment of the clamping head shaft in the same representation as in Fig. 5th

A clamping head for winding cores 10, generally designated 100 in the figures, consists of a clamping head shaft 20, a sleeve-shaped part serving as clamping head housing 30, and clamping pieces 40.

The winding cores 10 shown in the figures consist, as can be seen from FIGS. 1a / b, of circular cylindrical tubes with front ends 11 and a concentric recess 12 accessible from the front, into which the clamping head 100 can be inserted in the axial direction. Tubular winding sleeves are the most common, but in principle it is also possible to use closed cylindrical cylindrical bodies with corresponding recesses in the ends as winding sleeves.

The clamping head shaft 20 is shaped as a truncated pyramid, the base 21 of which is fastened to a plate 22. The plate 22 or the clamping head shank 20 itself are rotatably mounted on support arms in a manner known per se and may be driven in the direction of rotation about the axial direction B. The clamping head shaft is designed as a cantilever shaft, that is, it is supported on one side. With regard to its base 21 and its free end 23, the clamping head housing 30 is rotatably mounted. There is also one at its free end Restoring device 50 to be described later.

The six clamping surfaces 24 of the clamping head shank 20 are slightly inclined to the axial direction B and are straight in the direction of extension corresponding to the axial direction; on the other hand, the clamping surfaces 24 are concavely curved in the direction C of the clamping head circumference (see FIGS. 1c and 5), this concave curvature at the narrow end (free end 23) of the truncated pyramid being most pronounced and steadily decreasing to zero at the base 21. This can be seen particularly clearly from FIG. 5.

The six clamping pieces 40 evenly distributed on the circumference consist of pressure pieces 41 and sliding pieces 42, which are connected to one another in a manner known per se. Through an opening 43 of each clamping piece 40 in the circumferential direction, springs 44 are guided which (as can be seen from FIG. 1b) are designed as open rings and serve as return springs acting in the contraction sense. The sliders 42 are, as shown in Fig. 1a, rectilinear in the axial direction and, as can be seen from Fig. 5 and 6, convex in the transverse extent (circumferential direction C), so that their contact surface 45 with which they on the associated clamping surface 24 of the clamping head shaft 20 rest, are circular cylindrical in shape. The respective contact between the clamping piece and clamping head shaft takes place along a line of contact 46 (see FIGS. 5 and 6) - regardless of the size of the angle of rotation between the clamping head shaft and clamping piece.

The clamping head housing 30 has a cylindrical sliding surface 31 at the base end of the clamping head shaft and a cylindrical sliding surface 32 at the free end of the clamping head. At the base end, a flange-like, projecting stop 33 is connected in one piece to the clamping head housing or fastened to it. It forms a first end stop 34 for the front end 11 of the winding tube 10 and a second end stop 35 for the axial movement relative to the clamping head shaft 20, which interacts with the plate 22 (see FIG. 2a). The clamping head housing 30 is provided with elongated openings 36, within which the clamping pieces 40 are received and arranged to be radially displaceable. End stops 37 limit the maximum possible expansion path of the clamping pieces 40.

The reset device 50 is located in a conically tapered cover 51 which is connected to the clamping head housing 30, for. B. is rotatably connected by screws, not shown in the drawing. Within the cover 50, an annular or annular segment-shaped groove 52 is provided, in which two coil springs 53, a lid-fixed, i.e.. H. thus also stop 54 fixed to the housing and a driver 55 in the form of an annular segment. The driver 55 is non-rotatably attached to the free end of the clamping head shaft 20 via an arm 56 connected to it. The driver 55 and the arm 56 are shaped so that they can be rotated together within the cover 51 and with respect to the clamping head housing 30 against the restoring action of the springs 53. The springs 53 hold the clamping head housing 30 and the clamping head shaft 20 in a neutral rotational position with respect to one another, as long as the clamping head is outside the winding sleeve or the rotation between the clamping head shaft and the clamping head housing has not yet taken place, which is the case in the working positions according to FIGS. 1 and 2 . After rotation, one of the springs 53 is tensioned and the other spring 53 is relaxed or tensioned in the opposite direction. This can be seen from FIGS. 3c and 4c. The energy now stored in the compressed or expanded spring is only released again when the winding tube is removed from the clamping head.

From a comparison between Fig. 1a and 2a it can be seen that the maximum possible displacement in the axial direction B between the clamping head shaft 20 and the clamping head housing 30 is relatively small and by means of the driving arm 56 through the inner surface 57 of the cover 51 on the one hand and the end face 38 of the Clamping head housing 30 on the other hand is limited. In connection with the only slight taper of the clamping surfaces 24 of the clamping head shaft 20 relative to one another, this leads to the displacement-related expansion path of the clamping pieces 40 being relatively small. This is readily apparent from a comparison between FIGS. 1a and 2a. As a rule, it is not even necessary (although possible) for the radially outer pressure surfaces 47 of the clamping pieces 40 to touch the inner wall surfaces of the winding tube 10 when the displacement-related expansion path of the clamping pieces has been completed (see FIG. 2a). In this working position, there must only exist for a first, but still relatively minor frictional engagement between the winding tube 10 and the clamping head 100, so that when the clamping head is rotated against a tensile force acting on the winding tube periphery, there is a rotation between the clamping head housing and the clamping pieces on the one hand and the clamping head shaft on the other becomes possible. With such a twisting movement, a combined sliding and rolling movement takes place between the clamping head shaft and the clamping pieces. This can be seen particularly clearly from FIGS. 5 and 6. As a result, the clamping pieces are spread radially outward and spread firmly in the recess 12 of the winding tube 10 (see FIGS. 3a to 3c).

If the winding tube is to be pulled off the clamping head again, an axially outward force is exerted on the clamping head in a known manner. As a result, the clamping head shaft 20 withdraws from the clamping head housing 30 by a small sliding piece. The displacement-related expansion path of the clamping pieces is thereby reversed, which is supported by the return springs 44. This relatively small contraction path of the clamping pieces, which has already been completed in the illustration according to FIGS. 4a to 4c, is sufficient for the clamping head to be pulled out of the winding tube 10 with comparatively little force.

5 and 6 that the expansion path of the clamping pieces 40 and the sliding pieces 42 at the front and rear ends of the clamping pieces, as seen in the axial direction, is identical, because the clamping surfaces 24 have a constantly changing curvature along the clamping head shaft. Due to the gradual transition between the maximum curvature and the minimum curvature along the clamping head shank, the sliders rest on the clamping surfaces 24 along their entire length. The pressure surfaces 47 of the clamping pieces 40 thus remain axially parallel in all expansion or contraction positions. The required curvature geometry can be relatively easily determined mathematically. The same effect can also be achieved if the curvature, in particular the radius of curvature, of the contact surface 45 of the sliding pieces 42 changes continuously along the length of the clamping piece 40 or if different curvatures are provided both on the clamping head shaft and on the clamping pieces. The geometry shown in FIGS. 5 and 6, however, has the advantage of being particularly easy to control.

Claims (10)

1. Clamping head for winding tubes, on which material in web form, such as paper webs or similar is wound on or off, with

   - a polygonal clamping head shank (20 and

   - clamping pieces (40) abutting this clamping head shank, the clamping pieces (40) and the clamping head shank (2) capable of being rotated relative to one another and this rotation causing a radial movement (expansion/contraction path) of the clamping pieces (40),
   characterised in that

   - the clamping head shank (20) is a truncated pyramid,

   - the clamping pieces (40) and the clamping head shank (20) can be slid relative to one another in the axial direction (B),

   - the clamping pieces (40) are each provided with or effectively connected to an end limit stop (34 and 35) effective in the axial direction (B) for the winding tube (10) on the one hand and for the clamping head shank (20) on the other hand and

   - the clamping distance (expansion/contraction distance) of the clamping pieces (40) is composed of a rotation-related part and a sliding-related part, so that the (second) end limit stop (35) reaches its axial end position before reaching the end of the clamping distance.
2. Clamping head according to the precharacterising clause of patent claim 1,
   characterised in that

   - the clamping head shank (2) is a truncated pyramid,

   - the clamping pieces (40) and the clamping head shank (20) can be slid relative to one another in the axial direction (B),

   - the clamping pieces (40) are each provided with or effectively connected to an end limit stop (34 and 35) effective in the axial direction for the winding tube (10) on the one hand and for the the clamping head (20) on the other hand and

   - the lateral surfaces (clamping surfaces 24) of the clamping head shank (20) or the clamping pieces (40) contact surfaces (45) abutting these clamping surfaces or both of these surfaces are curved in the direction (C) of the clamping head periphery and the extent of the curvature along the axial direction (B) essentially progressively changes, so that a rotation between the clamping head shank (20) and the clamping pieces (40) leads to an identically long expansion/contraction path along the whole of the length of the clamping pieces (40) extending in the axial direction (B).
3. Clamping head according to Claim 1 characterised in that the lateral surfaces (clamping surfaces 24) of the clamping head shank (20) or the contact surfaces (45) of the clamping pieces (40) of both of these surfaces are curved in the direction (C) of the clamping head periphery and that the extent of curvature along axial direction (B) essentially changes progressively, so that a rotation between the clamping head shank (20) and the clamping pieces (40) leads to an identically long expansion/contraction path along the whole of the length of the clamping pieces (40) extending in axial direction (B).
4. Clamping head according to Claim 2 or 3 characterised in that the clamping surfaces (24) at the thicker end (base 21) of the clamping head shank (20) are straight and at the thinner end (free end 23) concavely curved or convexly curved at the thicker end and straight at the thinner end.
5. Clamping head according to one of the Claims 1 to 4 characterised in that the clamping surfaces (24) of the clamping head shank (20) or the contact surfaces (45) allocated to these clamping surfaces of the clamping pieces (40) or both of these surfaces are curved in the direction (C) of the clamping head periphery such that the mutual contact between the clamping head shank (20) and the individual clamping pieces (40) is essentially linear and permits at least a partial rolling-off movement between the clamping head shank and the individual clamping pieces.
6. Clamping head according to Claim 5 characterised in that the contact surfaces (45) of the clamping pieces (40) are circular cylindrical.
7. Clamping head according to one of the Claims 1 to 6 characterised by at least one spring (53) that can be placed under tension by rotation between the clamping pieces (40) and the clamping head shank (20) to restore rotation after the winding tube (10) is drawn off the clamping head (100).
8. Clamping head according to the Claim characterised in that the one spring (53) at least is a flat spiral spring that extends in the peripheral direction (C) of the clamping head (100).
9. Clamping head according to Claim 7 or 8 characterised in that the one spring (53) at least is supported in a housing section (clamping head housing 30), that can be rotated, and in particular also slid, with the clamping pieces (40) together relative to the clamping head shank (20), on a stop (54) fixed to the housing on the one hand and on the other hand on a carrier fixed to the clamping head shank (20).
10. Clamping head according to one of the Claims 1 to 9 characterised by a housing section (clamping head housing 30) carrying the clamping pieces (40) in particular in openings (36) and movable with the clamping pieces (40) relative to the clamping head shank in at least one direction.

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